Aberrant immune regulation likely represents one factor contributing to the increased incidence of immune-related disorders which accompany human aging. We propose to identify the cellular basis of this aberrent immune function by use of cross-over experiments between subsets of regular and effector cells of young and old, "normal" and "abnormal" individuals. We will examine the interaction and possible deleterious effects on the nervous system of abnormal immune products (monoclonal immunoglobulin, amyloid) likely resulting from immune dysregulation. With use of both monoclonal antibodies to enumerate regulator cell subsets and functional in vitro assays of regulator cell activity, we hope to determine how one can modulate regulator cell activity, either with immune products themselves, neurotransmitter agents, or pharmacological agents. Such studies are designed to identify the basis of change in immune regulation which accompanies human aging and to develop methods to modulate aberrant activity.